A wide variety of different breathing devices and resuscitators have been proposed, and many have been made. The simplest consist merely of a hand held mask with a manual valve. Usually a separate control unit was required for supplying gas to the mask.
Note complex units are known in which two or even three different modes of operation are possible. Again in these units the controls, for controlling the different modes, as well as the final gas pressure reducer were located in a separate component assembly and were not part of the mask patient valve assembly itself.
In the majority of even the more complex units the problem of changing over from one mode to the other in an emergency situation has involved various difficulties. Personnel must be highly trained, and must be capable of operating the unit with both hands at once, one on the mask and one on the control. These factors may interfere with the most effective use of the equipment. It will also be understood that such equipment will desirably be made available at locations where personnel may be less than adequately trained. Indeed, it is in just those hazardous locations i.e. remote from paramedic assistance, that emergencies are most likely to occur.
Clearly, it is desirable to provide such apparatus which is automatic in nature and which can be held and operated and controlled in one hand with both hands being able to remain on the mask/patient valve assembly and the patient so as to secure the mask to the patient in order to provide support to the jaw and, maintaining the patient airway, whilst creating an effective mask-to-face seal to reduce the potential for leaks at this junction.
The task of designing such an apparatus of such complexity, to fit within the palm of the hand is clearly beset with many difficulties. However, the advantages which will flow from such a self contained easily operated apparatus are many.
In such an improved apparatus it would be desirable to eliminate the separation of the controls from the patient valve, and to develop a device which gives more stable performance than other devices on the market, and to provide automatic patient override of the automatic cycling circuit in the event that the patient commences spontaneous respiration and demand breathing. This has not been achieved in any other single resuscitator unit.
Clearly such improved apparatus could be made available to a much wider number of persons with a much lower degree of training thereby placing the apparatus at the locations where emergencies are most likely to arise and require immediate treatment.
The improved apparatus should be capable of operating in an entirely automatic timed mode, for treatment of a patient who is not breathing, and should be capable of changing from the automatic mode to a demand mode when a person commences a natural inspiratory effort, and should also preferably be capable having the automatic mode overridden by a manual control mode for use by a trained paramedic.